Team:NRP-UEA-Norwich/NOSensing

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NRP UEA iGEM 2012

 

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Nitric Oxide Sensing & The Hybrid Promoters | The Comparator Circuit | Theoretical Projects

RUSSELL TO DO

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SUMMARY OF IT ALL HERE; similar to front page

. Produced new promoters - 2 BioBricks

. Ligated these to fluorescent proteins - 4 more BioBricks

. Promoter+FP BioBricks were characterised using growth studies and fluorometer, flow cytometry and FACS

. Aim to characterise further, such as finding maximum level of induction by certain compounds and difference in induction based on chemical used.

. Future applications in cancer and environment.

Contents

Introduction

The University of East Anglia hosts many research teams whose work focuses on studying nitrogenous species and the way in which bacteria use and modify those species. One major problem that is faced by these teams involves working with nitric oxide (NO), as NO is highly reactive with a low half life, therefore making it difficult to trace and quantitatively measure accurately. Many of the methods currently used to measure NO levels are unable to distinguish between homogenous species, such as nitrates (NO3) and nitrites (NO2), therefore the figure given for NO levels is often inaccurate as other nitrogenous species are taken into account.


The ability to be able to accurately detect NO levels is one with a great deal of potential for the future. Nitric oxide has been noted as a possible cancer therapy due to its physiological use as an apoptosis inducer by macrophages, however NO is also known to be used by cancerous cells to establish a baseline and use it to induce apoptosis and promote proliferation of a tumour; being able to accurately sense nitric oxide and go on to act on that information could be very useful to prevent the NO baseline being established by cancerous cells, but to also use NO for its apoptosis-inducing abilities. There are also other potential applications in the construction business, in 2008 NEED TO FIND REFERENCE OF PEOPLE released legislation encouraging construction companies to monitor their NO output as it is inversely proportional to carbon monoxide (a toxic substance which needs to be regulated); the ability to accurately detail levels of NO being released in these circumstances would be highly useful.


Nitric oxide is an extremely physiologically relevant molecule found within both eukarayotes and prokarayotes, where it is utilised by different enzymes and systems for various roles. The aim of the experiment was to devise a hybrid promoter that could be applied to eukarayotes and prokarayotes in order to begin to more accurately sense NO and report on its specific levels.

Experiments

. Looked at PyeaR and CArG, ligated them together in two orientations for a flexible promoter (info on what each is)

. Made into biobricks (link to registry page)

. Ligated to RFP/CFP and got photos to prove it works

. Used RFP/CFP with the fluorometer etc. to get data on sensitivity

. Tranfected into mammalian cells to show flexibility

. Studied the growth rate

Results

. Graphs from flow and fluorometer

. Pictures etc. from mammalian transfection

. Growth study on MB/BM

Conclusions

BM/MB better or the same, RFP/CFP better or the same etc.

Future Applications

Cancer

Warrior Cell

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A problem with current cancer therapeutic techniques is that they are not specific to cancer cells, leading to patient discomfort. We hope to engineer E.coli cells that selectively identifies cancerous cells through their anaerobic environment and secrete high concentrations of NO, mimicking macrophages, and thus killing these cells. These cells are known to be hypoxic, and hypoxia is a hallmark for cancer cells already used in tumour detection. Our Warrior Cell construct hopes to pave the way for a new kind of therapeutic strategy that delivers a therapeutic agent only when and where it is needed.

Buildings

Soil

Future Experiments

. Full quantitative analysis to see where the values lie; combine with tuners for different sensitivity levels

. With different substrates (e.g. nitrite salt, NO donor)

. With different reporter/effector enzyme